A tank that can't traverse broken or muddy terrain isn't going to be much use to anyone, and thus significant thought was given to the makeup of the suspension of German and Soviet tanks. While the Germans pursued ever more complex and versatile suspension, the Soviet engineers became famous for incorporating ruggedness and mechanical reliability into their more simple suspension systems.

The basic elements of a tank's suspension are its drive wheels, its roadwheels, its idler wheels, and its return rollers . The configuration of the roadwheels could produce a variety of different suspension systems, while the position of the drive wheels/idler wheels would produce different degrees of torque (how much engine horsepower would be converted into actual movement).

The most basic idea of a tank's drive system and suspension is as follows. The various wheels of a tank's suspension form a "frame" around which the tank's treads are laid. As the drive wheel turns, its gear teeth grip the treads and make them run around the other wheels in the tank's suspension much the same way a conveyor belt's belt moves over the rollers. The tread has a much greater grip on the ground than normal wheels would, and thus the tank can traverse a much greater variety of terrain than a normal wheeled vehicle.

The idler wheel is the wheel directly opposite the drive wheel, and is the extremity of the tank's suspension system. It is the wheel around which the treads traverse, and is thus essential. Notably, German enginners placed the idler wheel in the back and the drive wheel in the front while Soviet engineers fitted their tanks with a rear drive wheel and a forward idler wheel.

HOW TO LOCATE A TANK'S IDLER WHEEL

The idler wheel is either located at the front (Soviet tanks) or back (German tanks) of the tank's suspension system.